package com.abc.scholarship.config.security.utils;


import com.abc.scholarship.domain.entity.User;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Data
@ConfigurationProperties(prefix = "jwt")
@Component
public class JwtUtils {

    // 密钥
    private String secret;

    // 过期时间 毫秒
    private Long expiration;

    /**数据声明，生成令牌
     *
     * @param claims 数据声明
     * @return 令牌
     */
    private String generateToken(Map<String,Object> claims){
        Date expirationDate = new Date(System.currentTimeMillis()+expiration);
        return Jwts.builder().setClaims(claims)
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512,secret).compact();
    }

    /**从令牌中获取数据声明
     *
     * @param token 令牌
     * @return 数据声明
     */
    public Claims getClaimsFromToken(String token){
        Claims claims;
        try{
            claims = Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
        }catch (Exception e){
            claims = null;
        }
        return claims;

    }

    /**生成令牌
     *
     * @param userDetails
     * @return 令牌
     */
    public String generateToken(UserDetails userDetails){
        Map<String,Object> claims = new HashMap<>(2);
        claims.put(Claims.SUBJECT,userDetails.getUsername());
        claims.put(Claims.ISSUED_AT,new Date());
        return generateToken(claims);

    }

    /**从令牌中获取用户名
     *
     * @param token
     * @return 用户名
     */
    public String getUsernameFromToken(String token){
        String username;
        try{
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        }catch (Exception e){
            username = null;
        }
        return username;
    }

    /**判断令牌是否过期
     *
     * @param token
     * @return
     */
    public Boolean isTokenExpired(String token){
        Claims claims = getClaimsFromToken(token);
        Date expiration = claims.getExpiration();
        return expiration.before(new Date());
    }

    /**刷新令牌
     *
     * @param token
     * @return 新的令牌
     */
    public String refreshToken(String token){
        String refreshedToken;
        try{
            Claims claims = getClaimsFromToken(token);
            claims.put(Claims.ISSUED_AT,new Date());
            refreshedToken = generateToken(claims);
        }catch (Exception e){
            refreshedToken = null;
        }
        return refreshedToken;
    }

    /**验证令牌
     *
     * @param token
     * @param userDetails
     * @return
     */
    public Boolean validateToken(String token,UserDetails userDetails){
        User user = (User) userDetails;
        String username = getUsernameFromToken(token);
        return (username.equals(user.getUsername())&&!isTokenExpired(token));
    }
}
